export default {
	namespaced: true,

	state: () => ({
		cart: JSON.parse(uni.getStorageSync('cart') || '[]')
	}),

	mutations: {
		addToCart(state, goods) {
			// 根据提交的商品的Id，查询购物车中是否存在这件商品
			// 如果不存在，则 findResult 为 undefined；否则，为查找到的商品信息对象
			const findResult = state.cart.find((x) => x.goods_id === goods.goods_id)
			console.log(findResult);

			if (!findResult) {
				// 如果购物车中没有这件商品，则直接 push
				state.cart.push(goods)
			} else {
				// 如果购物车中有这件商品，则只更新数量即可
				findResult.goods_count++
			}
			// console.log(state.cart);
			this.commit('m_cart/saveToStorage')
		},
		saveToStorage(state) {
			uni.setStorageSync('cart', JSON.stringify(state.cart))
		},
		updateGoodsState(state, goods) {
			// 根据 goods_id 查询购物车中对应商品的信息对象
			const findResult = state.cart.find(x => x.goods_id === goods.goods_id)
			if (findResult) {
				findResult.goods_state = goods.goods_state
				this.commit('m_cart/saveToStorage')
			}
		},
		updateGoodsCount(state, goods) {
			const findResult = state.cart.find(x => x.goods_id === goods.goods_id)
			if (findResult) {
				findResult.goods_count = goods.goods_count
				this.commit('m_cart/saveToStorage')
			}
		},
		removeGoodsById(state, goods_id) {
			state.cart = state.cart.filter(x => x.goods_id !== goods_id)
			this.commit('m_cart/saveToStorage')
		},
		// 更新购物车中所有商品的勾选状态
		updateAllGoodsState(state, newState) {

			state.cart.forEach(x => x.goods_state = newState)
			this.commit('m_cart/saveToStorage')
		}
	},

	getters: {
		total(state) {
			// let c = 0
			// state.cart.forEach(x => c += x.goods_count)
			// return c

			return state.cart.reduce((total, item) => total += item.goods_count, 0)
		},
		checkedCount(state) {
			return state.cart.filter(x => x.goods_state).reduce((total, item) =>
				total += item.goods_count, 0)
		},
		checkedGoodsAmount(state) {
			// 先使用 filter 方法，从购物车中过滤器已勾选的商品
			// 再使用 reduce 方法，将已勾选的商品数量 * 单价之后，进行累加
			// reduce() 的返回值就是已勾选的商品的总价
			// 最后调用 toFixed(2) 方法，保留两位小数
			return state.cart.filter(x => x.goods_state)
				.reduce((total, item) => total += item.goods_count *
					item.goods_price, 0)
				.toFixed(2)
		}
	},
}